The James Webb Space Telescope turned its attention towards Saturn on June 25 for the first near-infrared observations of the ringed planet. While the planet itself appears a little dark in the image, its characteristic rings are quite bright. At the infrared wavelength, the planet appears dark in the image shared by NASA yesterday because methane gas absorbs nearly all the sunlight that falls on the planet’s atmosphere. But the icy rings reflect a lot of the light, creating the sharp contrast that can be seen in the image. Despite the seemingly overblown contrast, the image clearly shows the details of Saturn’s ring system and many of its moons, including Diione, Enceladus and Tethys. Researchers will follow up on this image with deeper exposures that will help them investigate the planet’s fainter rings, which are not visible in the image. The planet’s rings are made up of a variety of rocky and icy fragments, with individual particles ranging from the size of grains of sand to some that are as big as mountains on our planet. Recently, scientists used Webb to look at Enceladus and found a large plume of water spouting from the moon’s surface. This water feeds Saturn’s “E ring.” The Cassini spacecraft did image the planet’s atmosphere at greater clarity in the past but this is the first time that it is seen at this particular wavelength, 3.23 microns, since it is unique to Webb. If you think the image is missing something, you are right. Saturn is not sporting its familiar striped appearance. This is because the large, dark diffused structures in the planet’s northern hemisphere do not follow its lines of latitude. But it still has patchiness similar to Webb’s first NIRCam observations of Jupiter. There are also some differences between the northern and southern poles of the planet. Right now, the planet’s northern hemisphere is experiencing summertime while the southern hemisphere is just exiting a period of darkness at the end of winter. But the northern pole is particularly dark due to an unknown seasonal process that is affecting aerosols in the north in particular, according to NASA.
